4 Answers
4

You might be risking it by going against, as you say, accepted practice. Users are familiar with the up and down arrows. Your new icons look a bit like volume control to me which may confuse people.

Testing with users against the arrows will give you an indication as to how people may receive the new icons.

For alpha data you do see the A->Z, Z->A used sometimes. You could make icons of that and maybe something similar for numeric data (1->N, N->1 maybe). However, sometimes sort order is dependent on something else different to mere ordinal position in a set. For example, a bookstore may list books based on popularity, which underneath would be a numeric value but the title may be what is actually displayed. Deriving different icons for all types could be challenging.

Probably the reason that the arrows are generally used today is that they are quite generic and can be applied to any sort criteria. I think your icons could have done that too, but you are a bit late. Still, test them out on people and let us know how they go. I agree with you that the accepted arrows are perhaps not optimal.

With the arrows icon, I've seen that some people just don't bother about the ascending/descending meaning. They take a two-step approach: (1) click the column they want to sort on to sort on the right column; (2) change the sort order if necessary by clicking again.

Give your new icons a chance, and test them. Out of context they look a bit like volume controls as phinetune says, or they could be interpreted as sorting on "text length", but in the right context that may be different.

Yes, this is definitely worth testing: make a quiz showing each symbol and see if 5 out of 5 users can guess which sort polarity goes with each. Test on columns of numbers, dates, and names (for the last two, length of the display string is not necessarily related to value). In debrief see if users can guess that the symbol represents lines of text, as opposed to, say, a stylized (and ambiguous) arrow. @Wilson: Please post back in your question what you find.
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Michael ZuschlagJun 20 '11 at 12:04

It's a classic problem - whether you use arrows, A->Z or a vertical arrow with A above a Z or Z above an A (depending on order), the fact remains that users will not be sure whether this indicates current state or the state that will occur if you click the header. For this reason, so many people don't actually look at the arrow it self as an indicator of the actual direction but simply as an indicator of the functionality being available at all, or as an indicator of which column is being used to sort the data (in either direction)

As a result, people do tend to look at the data itself to determine the sorting direction and as Marielle says, the common result is that users click once and click again if they don't get what they expect. In particular this behavior is further forced on users by the confusion when clicking from one column header to the next, that the up or down ordering does not stay consistent and is neither remembered when clicking back to a previously ordered column (Thunderbird and other mail tools come to mind). Little wonder then, that from one application to the next, users do not discover a 'standard' for this small but important little bit of functionality.

This indicates a different approach should be required for the best user experience which prevents the user from having to think. The answer is not to indicate the sort order and the action in the column header but to provide a separate little control that clearly shows the current sort order and gives you a choice of other likely relevant sorting options. This is very common - and eBay has a good example of this:

Another issue is individual interpretations of what "ascending" and "descending" mean. We each know exactly what they mean ... to US. In my experience we have had a few instances where we discovered these truly do mean different things to different people. Ascending numbers to one person means smallest at the top and growing larger as you move down. To another, it means "up, stupid." You start at the bottom with the low numbers and "ascend" as you look up.
The A-Z in Excel and other sort affordances help with this.

Overwhelmingly, I have observed exactly what is noted above. Folks click the sort affordance, look at the results, and click again if it isn't right.